Copter: support logging while disarmed
Copter: remove extra in_mavlink_delay from should_log function

Also return false when logging disabled
Copter: add NearlyAll-AC315 LOG_BITMASK description
AP_Compass: added set_offsets() interface

this will be used by Replay to prevent the need for saving parameters
Replay: fixed loading of users parameters and parameter override

use compass.set_offsets() to avoid trying to write to storage
Parachute: set servo or relay to off position on every update

This resolves the issue of the parachute servo's position not being
initialised to the off position due to an ordering problem of the
auxiliary servos being initialised after the parachute object.
Copter: log DCM reported roll-pitch and yaw error
AP_Motors: reduce slow-start increment for fast CPUs